Overfill prevention valve

Abstract: An overfill prevention valve (12) is provided in the fill line of a tank (2). The valve (12) is arranged such that the valve (12) is held at a closed position unless an overflow for the tank is open. When the overflow plug (24) is removed from the outlet (22) causes the inlet (26) to be in fluid communication with the valve outlet (14) and allows the distribution network (16) and the tank (2) to be filled.

Description: The present invention relates to an overfill prevention valve. Such a valve is suitable for use in filling a tank or reservoir to a level determined by an outlet, such as an overflow, which, in normal use, is closed except during filling of the tank. Known self contained liquid circulation systems, such as oil cooling and/or lubrication systems, generally require a predetermined volume of fluid to be admitted into a tank (herein including a reservoir or a sump). Furthermore, the tank may not be filled directly, but the liquid may pass through a distribution network thereby priming the network before flowing into the tank. In such systems, it is known to fill the tank up to a level determined by a standpipe or some other overflow arrangement which is normally closed. Overfilling may occur if the overflow is inadvertently left closed during the filling operation. Such overfilling may give rise to increased churning of the liquid which may affect equipment performance and lead to elevated temperatures and internal pressures. US-4883148 discloses a filling valve according to the preamble of claim 1 for use with an engine oil reservoir which has an overflow drain passage closure member which must be removed in order to gain access to an inlet passage closure member. However, nothing prevents replacement of the closure member after the inlet passage has been opened, and thus there is no positive prevention of overfilling. According to the present invention there is provided an overfill prevention valve for use in conjunction with a fluid reservoir having a fluid inlet and a fluid overflow, the valve comprising a valve body having a first inlet for connection to a fluid supply, a first outlet for connection to said reservoir inlet in use, a second inlet for connection to said reservoir overflow in use, and a second outlet, there being an overflow passage establishing fluid flow communication between the second inlet and the second outlet, the valve further including a valve member moveable between an open position in which the first inlet has fluid flow communication with the first outlet and a closed position in which said communication is prevented, and, an overflow plug removably closing the second outlet and having a mechanical interrelationship with said valve member such that when the plug is in position closing the second outlet it holds the valve member in said closed position. Preferably said plug has an extended portion which, when the plug is closing the second outlet, abuts a portion of the valve member to hold the valve member in said closed position. Desirably said valve member is biased towards said open position for permitting fluid flow communication between the first inlet and the first outlet. Conveniently a spring is arranged to urge the valve member towards said open position. The present invention will further be decribed by way of example, with reference to the accompanying drawings, in which:- Figure 1 is a schematic diagram of an oil cooling/lubrication system incorporating an overflow prevention valve and tank arrangement constituting an embodiment of the present invention,. Figure 2 is a diagram of the valve shown in Figure 1 at a closed position; and Figure 3 is a diagram of the valve shown in Figure 2 at an open position. The cooling and lubrication system shown in Figure 1 comprises a tank 2 having an inlet 4 and an outlet 6, a pump 8 and an overflow prevention valve 12 having three inlets and two outlets. The outlet 6 of the tank 2 is connected to an inlet of a pump 8. An outlet of the pump 8 is connected to a third inlet 10 of an overflow prevention valve 12. A first outlet 14 of the valve 12 is connected to a distribution network 16. The distribution network 16 may include heat exchangers, filters and spray jets for spraying the oil onto bearings, and the like. An outlet from the distribution network 16 is connected to the inlet 4 of the tank 2. A stand pipe 18 extends from the base of the tank 2 thereby defining a maximum fill level. The stand pipe 18 is connected to a second inlet 20 of the overflow prevention valve 12. The second inlet 20 is in fluid flow communication with a second outlet 22 of the valve 12. A removable overflow plug 24 is provided for selectively opening or closing the second outlet 22. A first inlet 26 of the overflow prevention valve 12 is arranged to cooperate with a valve member 28 such that movement of the valve member 28 when the overflow plug 24 is removed from the second outlet 22 causes the first inlet 26 to be in fluid flow communication with the first outlet 14. The valve member 28 comprises an elongate member 32 movable within a cylinder 30, as shown in Figure 2. The member 32 carries an enlarged region 34 which is in substantially fluid sealed engagement with the cylinder 30. An annular chamber 36, bounded by the enlarged region 34, the cylinder 30 and a first end 38 of the valve member 28, is in constant fluid flow communication with the first outlet 14 and the third inlet 10. The first outlet 14 and the third inlet 10 are in fluid flow communication with the cylinder 30 at a first end thereof. A portion 40 of the valve member 28 extends through a passage 42, formed at a second end of the cylinder 30, and into a passage 44 defining the second outlet 22. A spring 45 is arranged to urge the valve member 28 towards the second end of the cylinder 30. The overflow plug 24 has a generally conical end section 46. When the overflow plug 24 is inserted into the second outlet 22 so as to close the second outlet, the overflow plug 24 bears against the portion 40 of the valve member 28 and urges the valve member to move to the position shown in Figure 2. Thus, the enlarged region 34 is positioned so as to prevent fluid flow communication between the first inlet 26 and the first outlet 14. Removal of the overflow plug 24 permits the valve member 28 to move under the urging of the spring 45 to the position shown in Figure 3, thereby permitting fluid flow communication between the first inlet 26 and the first outlet 14 via the chamber 36. Fluid flow communication between the first inlet 26 and the second outlet 22 is prevented by virtue of fluid sealed engagement between a conical seat 48 formed on the enlarged region 34 with a first end 50 of the passage 42. In order to fill the cooling and lubrication system shown in Figure 1, oil is supplied to the first inlet 26 of the overflow prevention valve 12. However, filling cannot commence until the overflow plug 24 has been removed from the second outlet 22. The pump 8 is either operated or designed so as to substantially prevent filling of the tank 2 occurring via the tank outlet 6. Thus, the oil supplied to the first inlet 26 of the valve 12 flows to the tank 2 via the annular chamber 36, the first outlet 14, the distribution network 16 and the tank inlet 4. Filling the tank 2 via the distribution network 16 ensures that the network 16 is primed. The tank 2 is prevented from being overfilled since excess oil will flow out of the tank 2 via the stand pipe 18 and the second inlet and outlet 20 and 22, respectively, of the overflow prevention valve 12. Thus inadvertent overfilling of the tank 2 due to failure to open the overflow outlet therefrom is avoided. In an alternative arrangement, a fill valve having a single inlet and outlet (corresponding to the first inlet 26 and outlet 14) and having a portion of a valve member extending therefrom, may be positioned adjacent an outlet of the stand pipe 18. The valve may be arranged such that the valve is closed when an overflow plug is inserted into the outlet of the stand pipe. It is thus possible to provide a simple and inexpensive apparatus for preventing the overfilling of a tank or similar reservoir.

Claims: An overfill prevention valve (12) for use in conjunction with a fluid reservoir (2) having a fluid inlet (4) and a fluid overflow (18), the valve (12) comprising a valve body having a first inlet (26) for connection to a fluid supply, a first outlet (14) for connection to said reservoir inlet (4), a second inlet (20) for connection to said reservoir overflow (18), and a second outlet (22), the valve (12) further including an overflow plug (24) removably closing said second outlet (22), and a valve member (28) moveable between an open position in which said first inlet (26) communicates with said first outlet (14) and a closed position in which fluid flow communication between said first inlet (26) and said first outlet (14) is prevented, the valve (12) being characterized by an overflow passage in said valve body interconnecting said second inlet (20) and said second outlet (22), and a mechanical interrelationship between said plug (24) and said valve member (28) whereby said plug (24) when closing said second outlet (22) holds said valve member (28) in said closed position preventing fluid flow communication between said first inlet (26) and said first outlet (14). An overfill prevention valve as claimed in Claim 1, characterized in that the plug (24) has an extending portion (46) which, when the plug (24) is positioned to close said second outlet (22), abuts a portion (40) of the valve member (28) and holds the valve member (28) in said closed position. An overfill prevention valve as claimed in Claim 1 or Claim 2, characterized in that the valve member (28) is biased towards said open position for permitting fluid flow communication between the first inlet (26) and the first outlet (14). An overfill prevention valve as claimed in Claim 3, characterized by a spring (45) arranged to urge said valve member (28) towards said open position.

Inventors: HOWARD RODNEY STUART, HOWARD, RODNEY STUART
Applicants: LUCAS IND PLC, LUCAS INDUSTRIES PUBLIC LIMITED COMPANY
Application year: 1994
Main classification: B67D5
IPC codes: F01M11, B67D7